How would a engine change affect the game design philosophy of Bethesda?
Performance? Visuals? Alright. But game design?
Creation Engine powers Starfield and Fallout New Vegas. Quests can be complex, dynamic, with multiple endings, with lots of ways to approach them. Or they can be flat fetch quests. The tools allow both and everything in between.
Bethesda just chooses to use the current game design framework and would choose the same on any other engine.
They are actually updating their game design principles. They stopped using game design documents, they simplified the quests, they try to make sure every play through gets to see as much content as possible. Maybe they should stop updating.